Radial profiles of the minority carrier lifetime of silicon specimens, obtained by the photoconductivity decay (PCD) method and the photocurrent method have been compared. The photocurrent method used on slices gives more or less the same spatial resolution as a modified PCD setup reported by Graff, used on cross-sectional bars. Some problems occur when the photocurrent method is applied to p-type silicon samples.

For each of the methods a typical application exists: the photocurrent method is an important and relatively easy-to-handle tool for the investigation of the lifetime behavior of silicon wafers during the heat treatment and oxidation process, and the PCD method enables a very fast test of the lifetime (and lifetime profiles) to be made on the starting ingot material.